AI predicts bowel cancer relapse risk with improved accuracy

A new AI system from La Trobe University could help clinicians forecast relapse risk in patients with stage-two bowel cancer—potentially enabling earlier, life-saving treatment for those most likely to recur. The work appears in Gastroenterology and centres on SÉMIL (Semantically-Enhanced Multiple Instance Learning), a model designed to extract prognostic signals from routine pathology.

Instead of relying on new biomarkers or additional tissue sampling, SÉMIL learns from two sources that pathology already produces: digital slide images and accompanying textual descriptions. This “semantic” integration allows the algorithm to interpret tumour features while preserving clinical context, turning everyday diagnostic materials into quantitative risk estimates.

In the study, researchers analysed more than 1,600 pathology slides and validated the model on 1,220 stage-two patients across three independent cohorts. The validation extended beyond a single site, drawing on data from multiple Australian institutions, a step aimed at testing robustness in real-world clinical variability.

Technically, SÉMIL evaluates tumour architecture at the invasive front—the boundary where cancer spreads into surrounding tissue. This region is considered prognostically important, yet difficult to label consistently between pathologists, partly because subtle growth patterns can be subjective.

The results show that each tumour can be assigned to a higher- or lower-risk group, supporting triage decisions after surgery. Importantly, when AI-based assessments aligned with evaluations by expert pathologists, the model produced the most accurate risk ratings.

Such performance matters because current Australian guidelines generally reserve chemotherapy for high-risk stage-two patients. If relapse risk can be determined more precisely, more patients could receive timely escalation—or spared when escalation is unlikely to help.

The researchers stress that the tool is intended to support clinical decision-making rather than replace it. By adding an “additional layer of information,” AI could help clinicians balance the benefits of chemotherapy against its side effects.

Beyond bowel cancer, the team envisions future systems that combine AI-derived pathology features with other emerging biomarkers to refine risk stratification and treatment planning in precision medicine.